4a=1.2.3.4+2.3.4(5-1)+3.4.5(6-2)+........+98.99.100(101-97)
4a=1.2.3.4+2.3.4.5-1.2.3.4+......+98.99.100.101-97.98.99.100
4a=98.99.100.101
a=(98.99.100.101):4=24497550
1x2x3+2x3x4+3x4x5+...+98x99x100
Tính tổng
1x2x3+2x3x4+3x4x5+...+98x99x100
Help me!!!
Tính nhanh:
1/1x2x3 + 1/2x3x4 + 1/3x4x5 + ... + 1/98x99x100
Tính :
a) 1/1x2+1/2x3+1/3x4+1/4x5+1/5x6+.....+1
b)1/1x2x3+1/2x3x4+1/3x4x5+.....+1/98x99x100
Tính :
a) 1/1x2+1/2x3+1/3x4+1/4x5+1/5x6+.....+1
b)1/1x2x3+1/2x3x4+1/3x4x5+.....+1/98x99x100
1/1x2x3 + 1/2x3x4 + ... + 1/98x99x100
Tính S=1x2x3+2x3x4+...+98x99x100
1x2x3+2x3x4+3x4x5+....+2018x2019
A=1x2x3+2x3x4+3x4x5+...+99.100.101